Archaeological soundings on the vaults of trajanic galleries 20a and 20b

In September-November 2012, we carried out an archaeological sounding in the sector of the Oppian Hill park above the outer surface of Trajanic Galleries 20A and 20B. The study was aimed at understanding the external layout and construction features of the ancient vaults, with a view both to reconstructing the missing parts and to defining the new external protection system for the monument. Below we publish the preliminary results of the archaeological study.

The galleries belong to a system of barrel-vaulted rooms built at the time of Trajan to subdivide the large open space of the Domus Aurea courtyard (Peristyle no. 20) and thus create the level area for the terrace of the Baths.

Location of Galleries 20A and 20B - SSBAR Archive

Location of Galleries 20A and 20B – SSBAR Archive

The two galleries studied are in a precarious state of conservation due above all to the loss of parts of the vaults in the past. They therefore form part of the conservation project for the NW corner of the Domus Aurea. This project entails structural consolidation, the reinstatement of continuity between the Neronian and Trajanic sectors and the microenvironmental isolation of the area.

Given the precarious state of conservation and the minimal thickness of the surviving vaults (about 15 cm at the crown), we needed to carry out some difficult propping work inside the two galleries to make it safe for artisans and archaeologists to enter the excavation area above.

Props and scaffolding erected to allow safe access to the excavation area - SSBAR Archive

Props and scaffolding erected to allow safe access to the excavation area – SSBAR Archive

Excavation above Gallery 20B: note the thickness of the vault at the top - SSBAR Archive

Excavation above Gallery 20B: note the thickness of the vault at the top – SSBAR Archive

The vaults of the Trajanic galleries are covered by a layer of earth about 1.20 m thick dating to the modern period, although it certainly consists in part of ancient stratigraphy, dug out and then replaced to raise the ground level to the park’s current height: inside this deposit are bone fragments, pottery sherds of the imperial and late imperial period together with evidently modern finds such as fragments of white enamelled ceramic plates and crockery. This accumulation shows that, at least in this area, the ancient layers have already been removed, perhaps to create the overlying park or during restoration work in the area during the late 1960s.

Modern earth layer covering the outer surfaces of the vaults - SSBAR Archive

Modern earth layer covering the outer surfaces of the vaults – SSBAR Archive

The surface brought to light by the removal of the earth layer, belonging to the exterior of the vaults of Trajanic Galleries 20A and 20B, presents a slight slope from south to north, from a height of 47.66 a.s.l. at the southern edge of the excavation to 47.49 a.s.l. at the northern edge. The concrete is characterized by the use of a fairly resistant pozzolana mortar and caementa consisting of medium-sized tufa chips.

An extremely interesting feature highlighted by the excavation is the identification of the “worksite phases” for the construction of the galleries and the connection between adjacent galleries:

Construction phases, rendering by Adriano Averini after C.F. Giuliani 1990 - SSBAR Archive

Construction phases, rendering by Adriano Averini after C.F. Giuliani 1990 – SSBAR Archive

after completing the construction of the perimeter walls of the various galleries (first phase) the wooden centering was put in place (second phase) on which concrete was cast to form the haunches of the vaults (third phase). Later a sort of abutment in earth and tufa chips was laid in the free space between the impost of one arch and the next, resting against that portion of the haunches that had previously been built (fourth phase).

Abutment earth between the imposts of the two adjacent galleries - SSBAR Archive

Abutment earth between the imposts of the two adjacent galleries – SSBAR Archive

This was followed by a further addition of concrete (fifth phase) which set onto the part of the vaults that had already been constructed, covering the earth abutment between adjacent vaults and forming a sort of screed linking the various galleries to one another.

The upper surface of this extremely smooth screed bears no traces of further floors above it, nor of the brick cavity found in other areas of the Trajanic terrace. From an altimetric point of view, on the other hand, the portion of outer surface brought to light (indicated on the plan by the letter L) which, as already said, has a height ranging from 47.66 to 47.49 a.s.l. is compatible with the similar surfaces found in soundings E, F and G opened in 2011 in the strip of park near today’s Via del Monte Oppio.

Location of Test Pits E, F, G and L in the Oppian Hill park - SSBAR Archive

Location of Test Pits E, F, G and L in the Oppian Hill park – SSBAR Archive

The excavation also brought to light a series of graves created by chiselling away the concrete of the Trajanic vaults. The burials are oriented east-west and are concentrated mainly near the haunches of the vaults, in other words where the structure is thickest. The subsequent conversion of the area into orchards and gardens led to the obliteration of the original ground surface from which the graves were dug, and the partial “mixing” of the original internal arrangement of the depositions, probably the origin of the bones found in the modern earth layer above. Of the only two tombs that have been fully excavated, Tomb 1 preserved the lower limbs and pelvis of an adult woman in a supine position, still anatomically connected.

Tomb 1 - SSBAR Archive

Tomb 1 – SSBAR Archive

Burial 2 yielded the severely compromised remains of an adult male skeleton, also in a supine position. In the absence of chronological indicators attributable with certainty to this funerary activity, it is not easy to give a precise date. Hypothetically, we can make a chronological and spatial correlation both with the tomb of the 5th-6th c. AD brought to light in Test Pit C and with the numerous burials (about 1000) of a similar date found in 1967 inside the so-called Sette Sale cistern.

Tomb 2 - SSBAR Archive

Tomb 2 – SSBAR Archive

Circular graves, rectangular depressions and linear grooves are further evidence of a new use of the area post-dating the establishment of the necropolis. These are fairly faint traces, also found inside the original Trajanic vaults, which seem to pave the way for a new arrangement of the area aimed at practices that we could describe as agricultural. These incisions suggest activities linked to the planting of trees or simple hedges.

Overview of the cuts into the concrete of the vaults - SSBAR Archive

Overview of the cuts into the concrete of the vaults – SSBAR Archive

A similar landscape can be ascribed to the system of vineyards and vegetable gardens attested on the Oppian Hill by the sources after the definitive abandonment of the Baths of Trajan.

The study was carried out under the Scientific direction of Elisabetta Segala and works management by Enrico del Fiacco; the excavation was carried out by Celis with archaeological assistance and documentation by the Cooperative Archeologia.

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Gli autori

Elisabetta Segala

Elisabetta Segala

Elisabetta Segala, Archaeologist. She has worked for the Soprintendenza Speciale per i beni Archeologici di Roma since 1982, in the Central Archaeological Area and on archaeological safeguard in the city’s 1st District (Municipio I). In 1992 she became a member of the Domus Aurea’s technical staff.
Anna Giulia Fabiani

Anna Giulia Fabiani

Archaeologist (Cooperativa Archeologia). She has worked professionally on rescue excavations in urban areas, coordinating archaeological activities in areas affected by the construction of major infrastructure (Lines B1 and C of the Rome Metropolitan railway) and the archaeological analysis of ancient monuments in conservation worksites in Rome’s Central Archaeological Area. From 2003, she has collaborated with SSBAR on various occasions for archaeological research in the Domus Aurea worksite.
Giovanni Ricci

Giovanni Ricci

Archaeologist (Cooperativa Archeologia). A specialist in urban archaeology, he coordinated the excavation of the monumental complex of Hadrian’s Athenaeum, found in Piazza Madonna di Loreto during work to construct Line C of the Rome Metropolitan railway. Since 2011, he has collaborated with SSBAR and the German Archaeological Institute in Rome on stratigraphic studies in the Domus Aurea worksite.

20 thoughts on “Archaeological soundings on the vaults of trajanic galleries 20a and 20b

  1. Pubblicazione molto interessante, grazie per averla condivisa con i lettori del blog!

  2. ma non esiste una bella galleria fotografica su come procedono i lavori?
    se c’è non l’ho trovata

    grazie
    buon lavoro

  3. Per dare un aggiornamento sullo stato dei lavori abbiamo puntato soprattutto sugli articoli che pubblichiamo di volta in volta corredati da un buon numero di fotografie supportate dal testo che – se pur sinteticamente – cerca di spiegare minuziosamente la natura dell’intervento. Una galleria fotografica da sola non sarebbe esaustiva rispetto alle varie e complesse opere che si affrontano all’interno della Domus.Tuttavia stiamo preparando una documentazione del tipo richiesto per gli ambienti in cui gli interventi sono giunti al termine.

  4. Pingback: ROMA ARCHEOLOGIA e BENI CULTURALI: LA SCOPERTA. Riaffiorate sepulture del V Secolo – Ecco la necropoli mai vasta

  5. Molto interessante la pratica di gettare in due tempi le volte per risparmiare materiale legante sul riempimento fra le stesse, avrei preferito delle foto piu’ grandi.
    Ho scoperto questo sito oggi da un link del corriere, lavoro in una impresa di costruzioni e sono affascinato dall’archeologia.
    Ancora complimenti e saluti!

  6. Molto bello questo diario scientifico. Complimenti a tutti gli autori. Userò questi materiali come caso di studio principale nel mio corso Tecnologias para a Conservação e o Restauro, Faculdade de Arquitectura e Planeamento Físico, Universidade Lúrio, Moçambique.
    Grazie da Maurizio.

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